Frequency-doubling technology, OCT help to detect glaucoma in eyes with normal visual fields

J Glaucoma. 2011;20(6):366-370.

Frequency-doubling technology perimetry combined with optical coherence tomography measurements may help identify early signs of glaucoma in eyes with suspected disease and normal visual fields, a study found.

"A glaucoma suspect is a person with suspicious optic discs or visual fields but without definite abnormality. Ocular hypertensive patients have raised intraocular pressure without optic disc or visual field damage," the study authors said. "There is need for a modality to distinguish these subjects from normal individuals to detect the disease as early as possible, even before the development of visual field loss as classically observed on [standard automated perimetry]. FDT perimetry may be a useful functional tool toward this end."

The prospective study included 60 eyes of 60 ocular hypertensive patients and 54 eyes of 54 subjects with optic disc features suggestive of glaucoma and normal visual fields. All patients underwent frequency-doubling technology (FDT) testing with the Welch Allyn frequency-doubling visual field instrument (Carl Zeiss Meditec). The Stratus spectral domain optical coherence tomography (Carl Zeiss Meditec) was used to measure average and inferior retinal nerve fiber layer (RNFL) thickness and disc area.

Study results showed a statistically significant correlation between FDT and average RNFL thickness measurements and optic disc area (both P < .001) among patients with suspect discs. There were no associations between FDT and vertical cup-disc area ratio.

In the ocular hypertension group, results showed a significant association between FDT and average RNFL thickness (P = .038). Data showed a significant negative correlation between FDT and vertical cup-disc area ratio, the authors reported.